Demonstration of the presence of aminoreductone formed during the Maillard reaction in milk

The Maillard reaction is a common chemical reaction that occurs in food and it generates multiple reaction products. Aminoreductone (AR) is one of the early-stage Maillard reaction products. At present the formation of AR has only been demonstrated in a model system consisting of a monosaccharide or disaccharide and an amino group-containing compound. There is no direct evidence to show the presence of AR in food. In this study, we demonstrated the formation and presence of AR in milk using a combination of 2,4-dinitrophenylhydrazine (DNP) and Cu2+. A DNP derivative of AR oxidised by Cu2+ was isolated and its detailed structure was identified by NMR analysis. We thus directly demonstrated the formation and presence of AR in milk.